This invention relates to a system for harvesting a generally cylindrical shaped tissue structure from the body of a patient. More particularly, the invention is directed to a system for harvesting a section of a blood vessel from a patient.
In certain circumstances it is desirable to remove sections of tubular tissue structure from a patient""s body. Such tissue may be used in another part of the patient""s body, may be transplanted into a second patient""s body or may be discarded. As used herein, the term xe2x80x9ctubular tissue structurexe2x80x9d includes blood vessels, tendons, bile ducts and any other similar tissue formation which is generally tubular in structure and capable of being separated from surrounding tissue. Although the invention herein will be discussed in terms of harvesting blood vessels it should be understood that the apparatus and method described are equally applicable to harvesting other tubular tissue structures from a human or animal body.
Vein harvesting is commonly done in connection with coronary artery bypass surgery. The saphenous vein is a subcutaneous vein which is often used for coronary artery bypass grafting, infra-inguinal bypass grafting and vein-vein bypass grafting. Other veins may also be used including the mammary vessel and the lessor saphenous vein. Previously, it has been necessary to make an incision along the full length of the vein section to be removed. The vein is then freed by severing and ligating the branches of the vein, after which the section of the vein can be removed from the patient. The full length incision must then be closed, for example by suturing or stapling. Obviously, the harvesting of the vein in this manner leaves disfiguring scars which are cosmetically undesirable. Additionally, the large incision creates a risk of infection to the patient and may not heal properly, especially with those patients who have poor circulation in their extremities. Such an incision may create a chronic wound.
Devices for harvesting a section of a blood vessel without creating a full-length incision have been suggested. U.S. Pat. No. 4,793,346 (Mindich) discloses a device for harvesting a section of a blood vessel by making only small incisions at opposite ends of the blood vessel section. The device includes a guide rod which fits inside the vein section and a tube having an inner diameter slightly larger than the outer diameter of the vein section to be harvested. The tube has one or more knife blades at the leading edge which are connected to an electrical supply. The vein section is removed by making the incision sufficiently deep so as to expose the ends of the blood vessel to be harvested. The blood vessel is cut to expose one end, the guide rod is inserted inside the blood vessel section, and the tube is placed over the end of the blood vessel section to be removed. The tube is then pushed along the blood vessel (into the patient) while rotating the tube to sever the branches of the blood vessel with the knife blade mounted at the leading edge of the tube. Electrical current is supplied to the knife blades to heat the blades and thereby cauterize the ends of the severed branches of the blood vessel. The procedure is continued until the tube has reached the second of the two incisions. The blood vessel is exposed and cut from the patient at the second incision. The tube is then removed from the patient with the blood vessel section inside the tube. The blood vessel section is then removed from the tube for further treatment and used as desired.
UK Patent No. GB 20 82 459A discloses a device for harvesting a section of a blood vessel similar to that disclosed in the Mindich patent. Again, two incisions are made, one at each end of the blood vessel section to be harvested. A guide rod is inserted into the blood vessel section through one of the incisions and a tube having a cutting element having a cutting tool at its operative end is passed over the blood vessel section and guide rod assembly. The tube is rotated as it passes over the blood vessel section to sever the connecting branches. After the tube has passed the entire length of the blood vessel section, the section is cut away through the second incision and the tube is removed from the patient with the harvested section inside the tube.
Blood vessel harvesting devices of this type have certain distinct disadvantages. While they eliminate the need for a full-length incision to remove the blood vessel segment, two incisions, one at each end of the segment to be harvested, are required in order to remove the blood vessel segment. For patients likely to develop chronic wounds, each additional incision increases the risk to the patient, and it is desirable to keep such incisions as close to the patient""s trunk as possible and to minimize the number and size of such incisions. Additionally, such devices are unable to adequately close off several branches of the blood vessel and thus are unable to adequately control bleeding. As a result, the patient suffers greater blood loss than is necessary. These prior devices may also remove more tissue than is necessary because the size of the cutting device is not readily adaptable to the changes in the size of the blood vessel.
In U.S. Pat. No. Re 36,043 (Knighton), an improved device and method for vein removal is disclosed which solve some of the problems associated with the use of prior art devices. Knighton discloses an endoscope having a lumen extending longitudinally through the scope body. The endoscope includes means for viewing an area adjacent the distal end of the lumen. The lumen has a lateral dimension large enough to accommodate the blood vessel being harvested and at least one tool for use in harvesting the blood vessel. A first end of the blood vessel section to be harvested is exposed through an incision in the patient""s body. A dissecting tool and a gripping tool are inserted through the lumen of the endoscope and used to dissect the blood vessel away from the surrounding connective tissue of the patient""s body. Additional tools are provided for use through the lumen of the endoscope to remove body fluids and coagulate bleeding tissue, to ligate and sever side branches from the blood vessel to be harvested, and to ligate and sever a distal end of the blood vessel to be harvested when a desired length of blood vessel has been dissected. Only a small incision in the patient""s body is necessary to harvest a relatively long length of blood vessel in a precise and controlled manner using this device and procedure.
U.S. Pat. No. 5,772,576 (Knighton et al.) also describes a device and method for vein removal. The device has one or more lumens extending through a body portion. One lumen is sized to accommodate a blood vessel and at least one tool for use in removing the vessel. The device may also include viewing means so that the operator may remotely view an area adjacent the distal end of the body portion. The device protects the vessel being removed from damage by the tools used in the procedure, which is critical since the blood vessel is destined for reuse (as in arterial bypass). In addition, a single operator can use the device.
However, there is still room for improvement in current vein harvesting devices. It is difficult to see the vein to be harvested, especially near the distal end, even with the use of optical fiber devices. Moreover, it can be difficult to position the tools needed to harvest a vein in a fast and efficient manner and minimize damage to vein and to the patient. Thus a need in the art remains for a convenient method that would effectively harvest a vein without causing any damage to it.
This invention is a system for the harvesting of a blood vessel. The system comprises a housing having a removable lower portion. In a preferred embodiment, the housing is configured to contain a body portion having at least one lumen. In a more preferred embodiment, the housing is configured to contain a multi-lumen body portion. Various tools are used in conjunction with the housing and the body portion for removal of a blood vessel.
In one aspect the invention is a method of removing a section of a generally cylindrical tissue structure from the body of a human or animal. The method includes providing a device having a first portion and a second portion, the first and second portions defining a working space therebetween, the second portion being movable with respect to the first portion; exposing a proximal end of the tissue structure section to be harvested through an incision in the body; inserting the device through the incision such that the second portion is positioned between the first portion and the tissue structure; moving the second portion with respect to the first portion to expose the working space between the first portion and the tissue structure; inserting at least one tool through the incision into the working space; dissecting the tissue structure away from surrounding tissue with the at least one tool; cutting a proximal end of the tissue structure section; cutting a distal end of the tissue structure section; and removing the tissue structure section through the incision.
The method may include providing a device wherein the first portion has a non-planar shape and the second portion is substantially planar, wherein the second portion is slidably engaged to the second portion and wherein the step of moving the second portion with respect to the first portion includes sliding the second portion out of engagement with the first portion.
In another aspect the invention is a system for removing a generally cylindrical tissue structure from a human or animal body. The system includes a device having an elongate nonplanar housing defining a longitudinal axis; a movable portion configured to be movable with respect to the housing from an engaged position where an at least partially enclosed working space is defined between the housing and the movable portion and a working position where the working space is exposed, the housing and movable portion being sized to be insertable through the incision and positioned adjacent the tissue structure; and at least one tool used in removing the tissue structure, the tool having a distal operative tip and being sized to be accommodated within the working space. The system may further comprise an elongate element having a first lumen sized for accommodating the tissue structure and a second lumen sized for accommodating at least one tool.
In one aspect the invention is a method of removing a generally cylindrical tissue structure from the body of a human or animal. The method comprises providing a means for creating a working space; exposing a proximal end of the tissue structure to be harvested through an incision in the body; inserting the means for creating a working space through the incision adjacent the tissue structure section; manipulating the means for creating a working space to form a working space adjacent the tissue structure section; inserting at least one tool through the incision into the working space between the tissue structure section and the means for creating a working space; dissecting the tissue structure away from surrounding tissue with the at least one tool; cutting a proximal end of the tissue structure section; cutting a distal end of the tissue structure section; and removing the tissue structure section through the incision. The method may further comprise providing an elongate element having first and second lumens and inserting a proximal end of the tissue structure section through the first lumen of the elongate device. Further, the method may comprise providing a substantially cylindrical dissection tool within the first lumen of the elongate member, the dissection tool having a third lumen, inserting a proximal end of the tissue structure section through the third lumen of the dissection tool, providing a cutting tool, and inserting the cutting tool through the second lumen of the elongate element.
In a further aspect the invention is a system for removing a generally cylindrical tissue structure from a lumen or animal body. The system comprises means for creating a working space adjacent the tissue structure in the body, the means being sized to be insertable into the body adjacent the tissue structure through an incision in the body, and at least one tool used in removing the tissue structure, the tool being sized to be accommodated within the working space.
The system may further comprise an elongate element having a first lumen sized for accommodating the tissue structure and a second lumen sized for accommodating at least one tool.
In another aspect the invention is a method for creating a working space for at least one tool over a generally cylindrical tissue structure in a human or animal body. The method comprises providing a device having a first portion and a second portion, the first and second portions defining a working space therebetween, the second portion being movable with respect to the first portion; making an incision in the body above the tissue structure; inserting the device through the incision such that the second portion is positioned between the first portion and the tissue structure; moving the second portion with respect to the first portion to expose the working space between the first portion and the tissue structure; and inserting the at least one tool through the incision into the working space.
In a further aspect the invention is a device for insertion through an incision for creating a working space for at least one tool adjacent a generally cylindrical tissue structure in a human or animal body. The device comprises an elongate nonplanar housing defining a longitudinal axis; and a movable portion configured to be movable with respect to the housing from an engaged position where an at least partially enclosed working space is defined between the housing and the movable portion and a working position where the working space is exposed, the housing and movable portion being sized to be insertable through the incision and positioned adjacent the tissue structure.